Test Your Skill In Reading Pediatric Lateral Necks
Radiology Cases in Pediatric Emergency Medicine
Volume 2, Case 20
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
     Interpreting lateral neck films usually involves 
children with respiratory infections, foreign bodies, or 
cervical spine conditions.  Case 10 in Volume 1 
reviewed the radiographic findings distinguishing 
several types of respiratory infections that result in 
airway symptoms (croup, retropharyngeal abscess, and 
epiglottitis).  Case 8 in Volume 1 reviewed some of the 
clinical and radiographic features of airway foreign 
bodies.  Cases 1 and 7 in Volume 2 reviewed some of 
the complications of esophageal and bronchial foreign 
bodies.  Case 5 in Volume 1 reviewed the radiographic 
features of C2-C3 pseudosubluxation versus true 
subluxation.  With this background information, 16 
lateral neck radiographs are contained in this case for 
review to test your interpretation skills.  No clinical 
information is given here.  Some of these films are soft 
tissue studies, while others are cervical spine studies.  
To conserve disk space, the images are limited to the 
area of interest only.
     A general approach to reviewing these radiographs 
can be more consistent if one adheres to a standard 
method of review.
     1.  Bony Alignment:  Line up the anterior borders of 
the vertebral bodies, the posterior borders of the 
vertebral bodies, the vertebral arches, and the spinous 
processes.
     2.  Height of the vertebral bodies and disk spaces.
     3.  Relationship of the odontoid (C2) and the atlas 
(C1).
     4.  Positioning of the neck:  Is the neck in flexion, 
extension, or neutral.
     5.  Width of the prevertebral soft tissue space.  This 
thickness is usually half the width of a vertebral body 
and should not exceed the width of a vertebral body.
     6.  Epiglottis:  Examine the shape of the epiglottis 
and the size of the pre-epiglottic space (vallecula).
     7.  Subglottic airway size.


View Case A.  


Interpretation of Case A
     1.  Bony Alignment:  Normal.  Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Extension.
     5.  Prevertebral space:  Slightly full, but less than the 
width of a vertebral body.
     6.  Epiglottis:  Thumb-like in appearance (white 
arrow).  It should normally appear thin or triangular.  
The pre-epiglottic space (black arrow) is narrow and 
nearly obliterated.
     7.  Subglottic airway size:  Satisfactory.
     Impression:  Epiglottitis.


View Case B.  



Interpretation of Case B
     1.  Bony Alignment:  Normal.  Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Extension.
     5.  Prevertebral space:  Widened (black arrow).  It is 
slightly thicker than the width of a vertebral body.
     6.  Epiglottis:  Thin.  The pre-epiglottic space is 
normal (wider than in Case A).
     7.  Subglottic airway size:  Satisfactory (white 
arrow).
     Impression:  Retropharyngeal abscess.


View Case C.  



Interpretation of Case C
     1.  Bony Alignment:  Normal.  Not able to see C7.  
Spinous processes are not included in the image.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Extension.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Thin.  The pre-epiglottic space is 
normal.
     7.  Subglottic airway size:  Narrowed.
     Impression:  Subglottic edema.  Croup.


View Case D.  



Interpretation of Case D
     1.  Bony Alignment:  Normal.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to fully see C7.
     3.  C1-C2:  Probably normal, difficult to see.
     4.  Positioning:  Extension.
     5.  Prevertebral space:  Borderline widening.  It is 
slightly less wide than the width of a vertebral body.  It 
is clearly wider than half of a vertebral body.
     6.  Epiglottis:  Thin.  The pre-epiglottic space is 
normal.
     7.  Subglottic airway size:  Image is too dark to see 
this.
     Impression:  Possible early retropharyngeal abscess.


View Case E.  


Interpretation of Case E
     1.  Bony Alignment:  Abnormal.  Note the 
malalignment of the posterior borders of the vertebral 
bodies.  C2 is anterior relative to C3.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
     3.  C1-C2:  Normal.
     4.  Positioning:  Flexion.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Not included in this view.
     7.  Subglottic airway size:  Not able to fully see the 
airway in this view.
     Impression:  Pseudosubluxation C2 on C3.  Case 5 
in Volume 1 reviewed this image.  Recall that films 
taken in flexion are likely to show this C2/C3 
pseudosubluxation.  This is distinguished from a 
hangman's fracture by the Swischuk line drawn 
between the anterior margin of the vertebral arches of 
C1 and C3.  This line should touch the anterior margin 
of the vertebral arch of C2 or come within 1 mm of it 
(see Volume 1, Case 5).


View Case F.  



Interpretation of Case F
     1.  Bony Alignment:  Normal.  Not able to see C6 
and C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C6 and C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Neutral.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Wide and thumb-like.  The 
pre-epiglottic space is narrow and shallow.
     7.  Subglottic airway size:  Difficult to see on this 
image.
     Impression:  Epiglottitis.


View Case G.  


Interpretation of Case G
     1.  Bony Alignment:  Normal.  Not able to see C6 
and C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C6 and C7.
     3.  C1-C2:  Not able to assess.
     4.  Positioning:  Extension.
     5.  Prevertebral space:  Widened.
     6.  Epiglottis:  Triangular.  The pre-epiglottic space is 
normal.
     7.  Subglottic airway size:  No narrowing.
     Impression:  Retropharyngeal abscess.


View Case H.   



Interpretation of Case H
     1.  Bony Alignment:  C2 is slightly anterior
with respect to C3.  However, Swischuk line is OK.  
Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Not able to 
fully see C6.  Not able to see C7.  The heights of C4 
and C5 are compressed, more so anteriorly.  C6 may 
also be compressed but it cannot be fully seen.
     3.  C1-C2:  Normal.
     4.  Positioning:  Flexion.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Not able to see it on this view.
     7.  Subglottic airway size:  Not able to fully assess it 
on this view.
     Impression:  Cervical spine compression fractures.


View Case I.  



Interpretation of Case I
     1.  Bony Alignment:  Normal.  Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Extension to neutral.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Wide and thumb-like.  The 
pre-epiglottic space is shallow.
     7.  Subglottic airway size:  Slight narrowing inferiorly.
     Impression:  Epiglottitis.


View Case J.  



Interpretation of Case J
     1.  Bony Alignment:  Normal.  Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Probably OK, but not able to fully see 
on this view.
     4.  Positioning:  Neutral.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Wide and thumb-like.  The 
pre-epiglottic space is shallow.
     7.  Subglottic airway size:  Normal.
     Impression:  Epiglottitis.


View Case K.  



Interpretation of Case K
     1.  Bony Alignment:  Normal.  Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Extension.
     5.  Prevertebral space:  Widened and bulging.
     6.  Epiglottis:  Thin.  The pre-epiglottic space is 
normal.
     7.  Subglottic airway size:  Normal.
     Impression:  Retropharyngeal abscess.


View Case L.  



Interpretation of Case L
     1.  Bony Alignment:  Normal.  Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Extension to neutral.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Thin.  The pre-epiglottic space is 
normal.
     7.  Subglottic airway size:  Mild narrowing.
     Impression:  Subglottic edema.  Croup.


View Case M.  



Interpretation of Case M
     1.  Bony Alignment:  Normal.  Not able to see C6 
and C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C6 and C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Extension.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Wide and thumb-like.  The 
pre-epiglottic space is very  shallow and almost 
obliterated.
     7.  Subglottic airway size:  Satisfactory.
     Impression:  Epiglottitis.


View Case N.  



Interpretation of Case N
     1.  Bony Alignment:  Normal.  Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Neutral.
     5.  Prevertebral space:  Widened and bulging.
     6.  Epiglottis:  Image is very dark in this region.  The 
prevertebral bulge is distorting this area.  The epiglottis 
cannot be adequately visualized in this view.
     7.  Subglottic airway size:  Satisfactory.
     Impression:  Retropharyngeal abscess.


View Case O.   



Interpretation of Case O
     1.  Bony Alignment:  Abnormal.  C2 is anterior 
relative to C3.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
     3.  C1-C2:  Normal.
     4.  Positioning:  Flexion.
     5.  Prevertebral space: Widened.
     6.  Epiglottis:  Difficult to see.  Partially covered by 
the hyoid bone.  Thin.  The pre-epiglottic space is 
normal.
     7.  Subglottic airway size:  Normal.
     Impression:  Pseudosubluxation.  The widened 
prevertebral space may suggest hemorrhage secondary 
to an occult cervical spine fracture.  However, in this 
instance, the widened prevertebral space is due to 
flexion positioning of the neck.  Prevertebral soft tissue 
widening may be merely an artifact if the patient's neck 
is in flexion.  In this case, both the pseudosubluxation 
and the widened prevertebral space would resolve if the 
radiograph was re-taken with the neck in extension.


View Case P.  



Interpretation of Case P        
     1.  Bony Alignment:  Normal.  Not able to see C7.
     2.  Vertebral bodies and disk spaces:  Normal sizes.  
Not able to see C7.
     3.  C1-C2:  Normal.
     4.  Positioning:  Extension.
     5.  Prevertebral space:  Not widened.
     6.  Epiglottis:  Triangular.  The pre-epiglottic space is 
slightly narrow, but it is deep and well preserved.
     7.  Subglottic airway size:  Narrowing noted.
     Impression:  Subglottic edema.  Croup.

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Web Page Author:
Loren Yamamoto, MD, MPH
Associate Professor of Pediatrics
University of Hawaii John A. Burns School of Medicine
loreny@hawaii.edu